Word Origin & History
mid-14c., "authoritative," from O.Fr. autentique (13c.), from M.L. authenticus, from Gk. authentikos "original, genuine, principal," from authentes "one acting on one's own authority," from autos "self" + hentes "doer, being." Sense of "entitled to acceptance as factual" is first recorded mid-14c. Authentic
implies that the contents of the thing in question correspond to the facts and are not fictitious; genuine implies that the reputed author is the real one. Related: Authenticity (1650s, in form authentity).